Demodectic Mange

Demodectic mange is an inflammatory skin condition caused by microscopic mites of the genus Demodex.

It is most common in young dogs and rare in cats.

Signs include scaly patches of bare skin, which may or may not be itchy.

Your veterinarian can diagnose the condition by taking a sample from your pet’s skin and examining it under a microscope.

The localized form typically resolves on its own without treatment.

The generalized form may be treated with oral or topical medications and antibiotics.

What Is Demodectic Mange?

Demodectic mange is an inflammatory skin condition caused by microscopic mites of the genus Demodex. These mites are transmitted from mother dogs and cats to their puppies or kittens during nursing and become normal inhabitants of the hair follicles. In small numbers, the mites usually don’t cause problems. However, in animals with certain genetic factors, metabolic disease, or a compromised immune system, the number of mites can increase, causing skin inflammation.

Demodectic mange usually occurs in dogs younger than 18 months and in older, immunocompromised dogs. Although it can be found in any breed, it is more common in certain purebred dogs, such as shar-peis, Dobermans, Great Danes, and Chihuahuas. Cats rarely get demodectic mange.

Is Demodectic Mange Contagious?

In general, demodectic mange is not considered a contagious disease. You will not get the mites from your pet, and other pets in your household will usually not be affected. As puppies and kittens grow, they usually develop immunity to the mites and do not experience skin infections. The mites are also selective about where they live. The species Demodex canis is most commonly found on dogs, while Demodex cati prefers cats.

What Are the Signs?

Animals may have localized or generalized demodectic mange. In the localized form, animals may lose one or more patches of hair, usually around the eyes and mouth, limbs, and trunk. The skin within the patches may be dry and flaky but is generally not itchy.

Animals with generalized demodectic mange lose hair in large areas over their entire body. The exposed skin is red and scaly and often becomes itchy, smelly, and painful because of secondary infections. Dogs with this form of demodectic mange should not be used for breeding because genetics often plays a part in this disease.

In some animals, hair loss may be limited to the paws. Affected areas are often red, and they may become infected and painful, causing your pet to limp.

How Is Demodectic Mange Diagnosed?

If your veterinarian suspects demodectic mange, he or she will scrape your pet’s skin or pluck some hair to search for mites. The mites tend to live deep within hair follicles, so your veterinarian will have to squeeze the skin and gently scrape several hairless patches with a scalpel blade until the area bleeds slightly to obtain samples that contain mites. He or she can then place these samples on a glass slide and look at them under a microscope to see the tiny mites.

If your veterinarian is unable to find mites but still suspects that they are they cause of the problem, he or she may recommend that a skin biopsy be performed. In other cases, your veterinarian may choose to treat your pet for demodectic mange to see if the condition improves with treatment.

In older dogs, demodectic mange is usually caused by a compromised immune system. If an older dog is affected, your veterinarian will most likely want to test for underlying conditions, such as a glandular disorder, liver or kidney disease, or cancer.

How Is Demodectic Mange Treated?

The localized form of demodectic mange generally resolves on its own within a few weeks or months and doesn’t require treatment. However, you should bring your pet in for a recheck exam to make sure the condition doesn’t become generalized.

Treatment for the generalized form requires patience. It may take several months before you see improvement. In some cases, the condition can’t be completely cured, only managed, and may come back. Your veterinarian has several options for treating demodectic mange. Some treatments are applied directly to the skin in the form of a dip or a spot-on solution that kills the mites. Other medications can be given by mouth. Because some treatments for demodectic mange have effects throughout the body, your veterinarian may recommend heartworm testing and additional blood tests for your dog before deciding which treatment to use. Your veterinarian will evaluate your dog’s condition and determine the best method of treatment for your pet. Regardless of which therapy is selected, treatment often must continue for many months, so be prepared for a lengthy commitment to therapy. Periodic skin scrapings should be performed to monitor treatment progress, and treatment often lasts for at least a month after the point when mites are not seen under the microscope.